Certain materials used in the manufacturing of composite articles have a limited shelf life. For example, pre-impregnated fiber-reinforced polymer matrix material (i.e., prepreg) is typically provided in material rolls that must be stored at a relatively low temperature to prevent premature curing of the prepreg prior to layup and curing of the prepreg during the manufacturing of a composite article. In a specific example, certain epoxy/carbon-fiber prepregs must be maintained at a temperature of approximately −10 degrees F. to attain a maximum shelf life of 12 months. Upon reaching its maximum shelf life, the roll of prepreg must be consumed or discarded. Prepreg is typically stored in a freezer to maintain the prepreg at the recommended storage temperature for maximum shelf life. Each roll of prepreg is typically date-stamped when shipped from the supplier. The date stamp of each material roll must be recorded when received at the manufacturer to facilitate the tracking of the remaining shelf life of the prepreg.
During a production program, a roll of prepreg may be removed from a freezer and taken to a composite layup area where a portion of the material may be removed for layup, after which the remainder of the material roll may be returned to the freezer. The amount of time that the prepreg is out of the freezer must also be recorded as out-time which may affect the shelf life of the prepreg. For large production programs such as for a commercial aircraft requiring a large quantity of different types of prepreg with high material-consumption rates, large capacity walk-in freezers are required for storing prepreg and other perishable materials. Such large capacity freezers are typically equipped with multiple storage racks each having a plurality of individual shelving units.
The current method for tracking each material roll includes recording the material type and remaining shelf life by monitoring the entrance and exit of materials from the freezer. The current record-keeping method relies on manual data entry, updating of spreadsheets, and physical inspections by material handlers when material rolls are moved in and out of the freezer. In this regard, the current method is tedious, error prone, and labor intensive for large capacity freezers with large material quantities and high material consumption rates. Furthermore, the current method does not provide a means for identifying the shelving unit containing the oldest material in the freezer. An additional drawback associated with the current method is that there is no way to determine the shortest travel distance from the freezer door to a specific shelving unit when retrieving and/or replacing material within the freezer, which would advantageously reduce the total amount of time spent moving inventory in and out of the freezer for a production program with high material consumption rates.
As can be seen, there exists a need in the art for an inventory management system and method that allows for improved tracking of perishable materials in an automated and cost-effective manner, and which additionally allows for quickly identifying the specific location within a storage area containing a desired material.